/Engine/Source/Runtime/GeometryCore/Public/DynamicMesh/Operations/MergeCoincidentMeshEdges.h
Returns true if endpoint vertices are within tolerance. Note that we do not know the order of the vertices here so we try both combinations.
bool IsSameEdge ( const FVector3d & a, const FVector3d & b, const FVector3d & c, const FVector3d & d ) const